Organic light-emitting diode display and method of manufacturing the same

ABSTRACT

An organic light-emitting diode (OLED) display and a method of manufacturing the same are disclosed. In one aspect, the display includes a plurality of pixel electrodes positioned over a substrate and separate from each other, a plurality of auxiliary wirings between the pixel electrodes, a pixel-defining layer over the pixel electrodes except for a central portion of the pixel electrodes and at least a portion of each of the auxiliary wirings, an intermediate layer over the pixel-defining layer and having a plurality of openings formed over the portion of each of the auxiliary wirings, and an opposite electrode positioned over the intermediate layer and facing the pixel electrodes, the opposite electrode electrically contacting the auxiliary wirings via the openings. The auxiliary wirings extend in a first direction and separate from each other by a first distance. The openings are aligned in a diagonal direction crossing the first direction.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No.10-2015-0163974, filed on Nov. 23, 2015 in the Korean IntellectualProperty Office, U.S. patent application Ser. No. 15/360,840 filed onNov. 23, 2016, now U.S. Pat. No. 10,297,656 issued May 21, 2019, andU.S. patent application Ser. No. 16/417,129 filed on May 20, 2019 thedisclosures of which are incorporated by reference herein in theirentirety.

BACKGROUND Field

The described technology generally relates to an organic light-emittingdiode display and a method of manufacturing the same.

Description of the Related Technology

In general, an organic light-emitting diode (OLED) display includes amatrix of pixels each having an OLED. The OLED includes a pixelelectrode, an opposite electrode facing the pixel electrode, and anintermediate layer between the pixel electrode and the oppositeelectrode and including an emission layer. In such an OLED display,pixel electrodes have island shapes formed by patterning each pixel, andan opposite electrode is provided as one body with respect to thepixels. In typical OLED displays, a voltage (IR) drop occurs in theopposite electrode, and thus, the pixels have unintended brightnessdifferences relative to each other.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

One inventive aspect relates to an OLED display that is easy tomanufacture and has high emission stability and a method ofmanufacturing the OLED display that is easy to manufacture and has highemission stability, so as to solve problems including the problemdescribed above. However, this is only an example, and does not pose alimitation on the scope of the inventive concept.

Another aspect is an OLED display that includes: a plurality of pixelelectrodes above a substrate and separate from each other; a pluralityof auxiliary wirings between the pixel electrodes, the auxiliary wiringsextending in a first direction and separate from each other by a firstdistance; a pixel-defining layer on the pixel electrodes and exposing atleast a portion of the pixel electrodes that includes a central portionof the pixel electrodes and at least a portion of the auxiliary wirings;an intermediate layer on the pixel-defining layer and including aplurality of openings that expose at least a portion of each of theauxiliary wirings and are in a diagonal direction crossing the firstdirection; and an opposite electrode on the intermediate layer andfacing the pixel electrodes, the opposite electrode electricallycontacting the auxiliary wirings via the openings.

In the present embodiment, a portion of the intermediate layer that isadjacent to the openings is transformed by strong heat.

In the present embodiment, the auxiliary wirings includes a firstauxiliary wiring and a second auxiliary wiring separate from the firstauxiliary wiring by a second distance, the openings may include a firstopening that exposes at least a portion of the first auxiliary wiringand a second opening that exposes at least a portion of the secondauxiliary wiring, and the first opening and the second opening may shiftin the diagonal direction.

In the present embodiment, the second distance is identical to the firstdistance.

In the present embodiment, the second distance is n times the firstdistance.

In the present embodiment, the openings further include a third openingand a fourth opening that are most adjacent to the first opening and thesecond opening respectively in a second direction perpendicular to thefirst direction, and a shape obtained by connecting vertices of thefirst opening, the second opening, the third opening, and the fourthopening to each other may be a parallelogram.

In the present embodiment, the apparatus further includes an emissionlayer between the pixel electrodes and the opposite electrode, theemission layer corresponding to each of the pixel electrodes.

In the present embodiment, the apparatus further includes a plurality ofsub-wirings extending in a second direction perpendicular to the firstdirection.

In the present embodiment, the auxiliary wirings and the sub-wirings areelectrically connected to each other via contact holes.

Another aspect is a method of manufacturing an OLED display. The methodincludes: forming a plurality of pixel electrodes above a substrate, thepixel electrodes being separate from each other; forming a plurality ofauxiliary wirings between the pixel electrodes, the auxiliary wiringsextending in a first direction and separate from each other by a firstdistance; forming a pixel-defining layer on the pixel electrodes, thepixel-defining layer exposing at least a portion of the pixel electrodesthat includes a central portion of the pixel electrodes and at least aportion of the auxiliary wirings; forming an intermediate layer over theentire surface of the substrate, the intermediate layer covering thepixel-defining layer; forming a plurality of openings in theintermediate layer that expose at least a portion of each of theauxiliary wirings and are in a diagonal direction crossing the firstdirection; and forming, on the intermediate layer, an opposite electrodethat faces the pixel electrodes, the opposite electrode electricallycontacting the auxiliary wirings via the openings.

In the present embodiment, the forming of the openings includes formingthe openings by irradiating a laser beam on the intermediate layer.

In the present embodiment, the forming of the auxiliary wirings includesforming a first auxiliary wiring and forming a second auxiliary wiringseparate from the first auxiliary wiring by a second distance, theforming of the openings may include forming a first opening that exposesat least a portion of the first auxiliary wiring and forming a secondopening that exposes at least a portion of the second auxiliary wiring,and the first opening and the second opening may shift in the diagonaldirection.

In the present embodiment, the second distance is identical to the firstdistance.

In the present embodiment, the second distance is n times the firstdistance.

In the present embodiment, the forming of the openings includes forminga third opening that is most adjacent to the first opening in a seconddirection perpendicular to the first direction and forming a fourthopening that is most adjacent to the second opening in the seconddirection perpendicular to the first direction, and a shape obtained byconnecting vertices of the first opening, the second opening, the thirdopening, and the fourth opening to each other may be a parallelogram.

In the present embodiment, the method further includes forming anemission layer between the pixel electrodes and the opposite electrode,the emission layer corresponding to each of the pixel electrodes.

These general and specific embodiments may be implemented by using asystem, a method, a computer program, or a combination thereof.

An organic light-emitting diode (OLED) display comprising: a substrate;a plurality of pixel electrodes positioned over the substrate andseparate from each other; a plurality of auxiliary wirings between thepixel electrodes, the auxiliary wirings extending in a first directionand separate from each other by a first distance; a pixel-defining layerover the pixel electrodes except for a central portion of the pixelelectrodes and at least a portion of each of the auxiliary wirings; anintermediate layer over the pixel-defining layer and having a pluralityof openings formed over the portion of each of the auxiliary wirings,wherein the openings are aligned in a diagonal direction crossing thefirst direction; and an opposite electrode positioned over theintermediate layer and facing the pixel electrodes, the oppositeelectrode electrically contacting the auxiliary wirings via theopenings.

In the above display, a portion of the intermediate layer that isadjacent to the openings is configured to be transformed by heat.

In the above display, the auxiliary wirings comprise a first auxiliarywiring and a second auxiliary wiring separate from the first auxiliarywiring by a second distance, wherein the openings comprise a firstopening formed over at least a portion of the first auxiliary wiring anda second opening formed over at least a portion of the second auxiliarywiring.

In the above display, the second distance is the same as the firstdistance.

In the above display, the second distance is n times longer than thefirst distance, and wherein n is a natural number.

In the above display, the openings further comprise a third opening anda fourth opening that are respectively located closest to the firstopening and the second opening in a second direction crossing the firstdirection, wherein the first to fourth openings have a parallelogramshape.

The above display further comprises an emission layer between the pixelelectrodes and the opposite electrode.

The above display further comprises a plurality of sub-wirings extendingin a second direction crossing the first direction.

In the above display, the auxiliary wirings and the sub-wirings areelectrically connected to each other via a plurality of contact holes.

Another aspect is a method of manufacturing an organic light-emittingdiode (OLED) display, the method comprising: forming a plurality ofpixel electrodes over a substrate, the pixel electrodes being separatefrom each other; forming a plurality of auxiliary wirings between thepixel electrodes, the auxiliary wirings extending in a first directionand separate from each other by a first distance; forming apixel-defining layer over the pixel electrodes except for a centralportion of the pixel electrodes and at least a portion of each of theauxiliary wirings; forming an intermediate layer over the entire surfaceof the substrate, the intermediate layer covering the pixel-defininglayer; forming a plurality of openings in the intermediate layer thatrespectively expose at least a portion of each of the auxiliary wirings,wherein the openings are aligned in a diagonal direction crossing thefirst direction; and forming an opposite electrode that faces the pixelelectrodes over the intermediate layer, the opposite electrodeelectrically contacting the auxiliary wirings via the openings.

In the above method, the forming of the openings comprises irradiating alaser beam on the intermediate layer.

In the above method, the forming of the auxiliary wirings comprisesforming a first auxiliary wiring and forming a second auxiliary wiringseparate from the first auxiliary wiring by a second distance, whereinthe forming of the openings comprises forming a first opening thatexposes at least a portion of the first auxiliary wiring and forming asecond opening that exposes at least a portion of the second auxiliarywiring.

In the above method, the second distance is to the same as the firstdistance.

In the above method, the second distance is n times longer the firstdistance, and wherein n is a natural number.

In the above method, the forming of the openings comprises i) forming athird opening that is located closest to the first opening in a seconddirection crossing the first direction and ii) forming a fourth openingthat is located closest to the second opening in the second directionand wherein the first to fourth openings have a parallelogram shape.

The above method further comprises forming an emission layer between thepixel electrodes and the opposite electrode.

Another aspect is an organic light-emitting diode (OLED) displaycomprising: a substrate; a plurality of pixel electrodes formed over thesubstrate; a plurality of auxiliary wirings between the pixelelectrodes, the auxiliary wirings extending in a first direction; anintermediate layer formed over the auxiliary wirings and having aplurality of openings formed therethrough; and an opposite electrodeformed over the intermediate layer and electrically connected to theauxiliary wirings via the openings.

In the above display, the auxiliary wirings include first and secondauxiliary wirings adjacent to each other, wherein the openings includefirst and second openings respectively formed over the first and secondauxiliary wirings, and wherein the first and second openings are notaligned in a second direction perpendicular to the first direction.

In the above display, the auxiliary wirings further include third andfourth auxiliary wirings adjacent to each other, wherein the third andfourth auxiliary wirings are respectively separated from the first andsecond auxiliary wirings by at least two interposed auxiliary wirings,wherein the openings further include third and fourth openingsrespectively formed over the third and fourth auxiliary wirings, andwherein the third and fourth openings are not aligned in the seconddirection.

The above display further comprises a metal layer interposed between andelectrically connecting the auxiliary wirings and the oppositeelectrode.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic plan view of an OLED display according to anembodiment.

FIG. 2 is an enlarged view of part 11 of FIG. 1.

FIG. 3 is a schematic cross-sectional view taken along line of FIG. 2.

FIG. 4 is a schematic plan view of an OLED display according to anembodiment.

FIG. 5 is an enlarged view of part V of FIG. 4.

FIGS. 6, 7, 8 and 9 are schematic cross-sectional views of a process ofmanufacturing an OLED display according to an embodiment.

DETAILED DESCRIPTION OF CERTAIN INVENTIVE EMBODIMENTS

As the described technology allows for various changes and numerousembodiments, exemplary embodiments will be illustrated in the drawingsand described in detail in the written description. Advantages andfeatures of one or more exemplary embodiments and methods ofaccomplishing the same may be understood more readily by reference tothe following detailed description of the one or more exemplaryembodiments and the accompanying drawings. The described technology may,however, be embodied in many different forms and should not be construedas being limited to the one or more exemplary embodiments set forthherein.

Reference will now be made in detail to exemplary embodiments, examplesof which are illustrated in the accompanying drawings. Like referencenumerals in the drawings denote like elements, and a repeateddescription thereof will be omitted. The term “and/or” used hereinincludes any and all combinations of one or more of the associatedlisted items.

While such terms as “first” and “second” may be used to describe variouscomponents, such components must not be limited to the above terms. Theabove terms are used only to distinguish one component from another. Thesingular forms “a,” “an,” and “the” used herein are intended to includethe plural forms as well, unless the context clearly indicatesotherwise.

It will be understood that the terms such as “include,” “comprise,” and“have” used herein specify the presence of stated features orcomponents, but do not preclude the presence or addition of one or moreother features or components.

Sizes of components in the drawings may be exaggerated for convenienceof explanation. In other words, since sizes and thicknesses ofcomponents in the drawings are arbitrarily illustrated for convenienceof explanation, exemplary embodiments are not limited thereto.

The x-axis, the y-axis and the z-axis are not limited to three axes ofthe rectangular coordinate system and may be interpreted in a broadersense. For example, the x-axis, the y-axis, and the z-axis may beperpendicular to one another or may represent different directions thatare not perpendicular to one another.

When an embodiment may be implemented differently, a specific processorder may be performed differently from the described order. Forexample, two consecutively described processes may be performedsubstantially at the same time or performed in an order opposite to thedescribed order. In this disclosure, the term “substantially” includesthe meanings of completely, almost completely or to any significantdegree under some applications and in accordance with those skilled inthe art. Moreover, “formed, disposed or positioned over” can also mean“formed, disposed or positioned on.” The term “connected” includes anelectrical connection.

FIG. 1 is a schematic plan view of an OLED display 1 according to anembodiment. FIG. 2 is an enlarged view of part II of FIG. 1. FIG. 3 is aschematic cross-sectional view taken along line III-III of FIG. 2.

Referring to FIGS. 1 to 3, the OLED display 1 includes a plurality ofpixel electrodes 210 above a substrate 100, a plurality of auxiliarywirings 160 a between the pixel electrodes 210, a pixel-defining layer180 on the pixel electrodes 210, an intermediate layer 221 and 222including a plurality of openings 230 a that expose at least a portionof a plurality of auxiliary wirings 160 a 1 to 160 an, and an oppositeelectrode 230 electrically contacting the auxiliary wirings 160 a 1 to160 an via the openings 230 a.

The substrate 100 may be formed of one or more materials, for example,glass, metal, or plastic such as polyethylene terephthalate (PET),polyethylene naphthalate (PEN), or polyimide. The substrate 100 mayinclude a display area DA where a plurality of pixels is arranged and aperipheral area PA surrounding the display area DA.

The pixel electrodes 210 may be in the display area DA. The pixelelectrodes 210 may be directly on the substrate 100, or over thesubstrate 100 with various layers including a thin film transistor TFTbetween the substrate 100 and the pixel electrodes 210. The pixelelectrodes 210 may be separate from each other and arranged in a certaindirection. That is, as illustrated in FIG. 2, the pixel electrodes 210may be arranged in x and y directions to form a matrix.

The auxiliary wirings 160 a 1 to 160 an may be between the pixelelectrodes 210. The auxiliary wirings 160 a 1 to 160 an are electricallyconnected to the opposite electrode 230, which will be described below,and thus, decrease an IR drop of the opposite electrode 230. Theauxiliary wirings 160 a may extend in a first direction (y-axisdirection) and may be separate from each other by a first distance d.The auxiliary wirings 160 a 1 to 160 an may be on the same layer as thepixel electrodes 210 or may be on the same layer as one of theelectrodes constituting the thin film transistor TFT. In the presentembodiment, as illustrated in FIG. 3, the auxiliary wirings 160 a may beon the same layer as a source electrode 160 s or a drain electrode 160 dof the thin film transistor TFT or may be formed of the same material asthe source electrode 160 s or the drain electrode 160 d of the thin filmtransistor TFT.

The pixel-defining layer 180 may be on the pixel electrodes 210. Thepixel-defining layer 180 may expose at least a portion of the pixelelectrodes 210 that includes a central portion of the pixel electrodes210 and at least a portion of the auxiliary wirings 160 a 1 to 160 an.The pixel-defining layer 180 may include an opening that exposes atleast a portion of the pixel electrodes 210 that includes a centralportion of the pixel electrodes 210, that is, an opening thatcorresponds to each sub-pixel, and thus may define a pixel. Also, thepixel-defining layer 180 may increase a distance between an end portionof the pixel electrodes 210 and the opposite electrode 230 that will beabove the pixel electrodes 210 later and thus may prevent an arc or thelike from occurring in the end portion of the pixel electrodes 210.

The intermediate layer 221 and 222 and an emission layer 223 may be onthe pixel-defining layer 180. The intermediate layer 221 and 222 mayhave a single-layered or multi-layered structure, and as illustrated inFIG. 3, may be disposed over the entire surface of the substrate 100.That is, unlike the emission layer 223, the intermediate layer 221 and222 may entirely cover the top surface of the pixel-defining layer 180.The intermediate layer 221 and 222 may include one or more selected froma hole injection layer (HIL), a hole transport layer (HTL), an electrontransport layer (ETL), and an electron injection layer (EIL).

The intermediate layer 221 and 222 may include a first intermediatelayer 221 and a second intermediate layer 222. In this regard, the firstintermediate layer 221 may include an opening 221′, and the secondintermediate layer 222 may include an opening 222′. That is, theopenings 230 a illustrated in FIG. 2 may each include the opening 221′in the first intermediate layer 221 and the opening 222′ in the secondintermediate layer 222.

The first intermediate layer 221 may have a single-layered ormulti-layered structure. For example, when the first intermediate layer221 is formed of a polymer, the first intermediate layer 221 may includea single HTL, the HTL including poly-(3,4)-ethylene-dihydroxy thiophene(PEDOT) or polyaniline (PANI). When the first intermediate layer 221 isformed of a low molecular material, the first intermediate layer 221 mayinclude an HIL and an HTL.

The second intermediate layer 222 may be optionally formed. For example,when the first intermediate layer 221 and the emission layer 223 eachinclude a polymer, the second intermediate layer 222 may be omitted.When the first intermediate layer 221 and the emission layer 223 eachinclude a low molecular material, the second intermediate layer 222 maybe formed to obtain an OLED having excellent characteristics. In thiscase, the second intermediate layer 222 may have a single-layered ormulti-layered structure and may include an ETL and/or an EIL.

The intermediate layer 221 and 222 may include the openings 230 aexposing at least a portion of the auxiliary wirings 160 a 1 to 160 an.The openings 230 a may be in a diagonal direction (direction A) crossingthe first direction (y-axis direction) in which the auxiliary wirings160 a 1 to 160 an extend. Although it is illustrated in FIG. 2 that theopenings 230 a are provided for every five pixel electrodes 210 each inwidth and length, the disclosure is not limited thereto. A position inwhich the openings 230 a are repeatedly formed may be changed dependingon the size of a display area (active area).

Referring to FIG. 2 again, the auxiliary wirings 160 a 1 to 160 aninclude a first auxiliary wiring 160 a 1 and a second auxiliary wiring160 a 2 adjacent to the first auxiliary wiring 160 a 1. The secondauxiliary wiring 160 a 2 may be separate from the first auxiliary wiring160 a 1 by a second distance, and in this regard, the second distancemay be identical to the first distance d or may be n times the firstdistance d. That is, when the second distance is identical to the firstdistance d, the second auxiliary wiring 160 a 2 may be right next to thefirst auxiliary wiring 160 a 1. When the second distance is n times thefirst distance d, the second auxiliary wiring 160 a 2 may not be rightnext to the first auxiliary wiring 160 a 1.

The openings 230 a may include a first opening 230 a 1 and a secondopening 230 a 2. The first opening 230 a 1 may expose at least a portionof the first auxiliary wiring 160 a 1, and the second opening 230 a 2may expose at least a portion of the second auxiliary wiring 160 a 2. Inthis regard, the first opening 230 a 1 and the second opening 230 a 2may be shifted in the diagonal direction (direction A). Accordingly, thefirst opening 230 a 1 and the second opening 230 a 2 shifted from thefirst opening 230 a 1 by a predetermined distance may be above differentauxiliary wirings from each other, and as such a pattern is repeated,current may be prevented from concentrating into a certain auxiliarywiring.

The openings 230 a may further include a third opening 230 a 3 and afourth opening 230 a 4 in addition to the first opening 230 a 1 and thesecond opening 230 a 2. The third opening 230 a 3 may be most adjacentto the first opening 230 a 1 in a second direction (x-axis direction)perpendicular to the first direction (y-axis direction). Similarly, thefourth opening 230 a 4 may be most adjacent to the second opening 230 a2 in the second direction (x-axis direction) perpendicular to the firstdirection (y-axis direction). In this regard, a shape obtained byconnecting respective vertices of the first opening 230 a 1, the secondopening 230 a 2, the third opening 230 a 3, and the fourth opening 230 a4 may be a parallelogram. That is, when the first opening 230 a 1 andthe third opening 230 a 3 are parallel to each other in the seconddirection (x-axis direction), and the second opening 230 a 2 and thefourth opening 230 a 4 are also parallel to each other in the seconddirection (x-axis direction), the second opening 230 a 2 is shifted fromthe first opening 230 a 1 by a predetermined distance in the diagonaldirection (direction A), and the fourth opening 230 a 4 is shifted fromthe third opening 230 a 3 by a predetermined distance in the diagonaldirection (direction A).

When the first opening 230 a 1 and the second opening 230 a 2 are not inthe diagonal direction (direction A) but consecutively in the firstdirection (y-axis direction) along a certain auxiliary wiring, forexample, the first auxiliary wiring 160 a 1, current concentrates intothe first auxiliary wiring 160 a 1. This degrades the performance of anauxiliary wiring formed to lower the IR drop of the opposite electrode230. Accordingly, in the OLED display 1, when the openings 230 a viawhich the auxiliary wirings 160 a 1 to 160 an and the opposite electrode230 may electrically contact each other are formed, the openings 230 amay be shifted as much as a predetermined distance in the diagonaldirection (direction A) and thus may be above different auxiliarywirings from each other. Accordingly, current may be prevented fromconcentrating into a certain auxiliary wiring.

Next, a cross-sectional structure of the OLED display 1 will be mainlydescribed in the following with reference to FIG. 3.

The thin film transistor TFT and a capacitor CAP may be disposed abovethe substrate 100, and an OLED electrically connected to the thin filmtransistor TFT may be placed above the substrate 100. The thin filmtransistor TFT includes a semiconductor layer 120 formed of amorphoussilicon, polycrystalline silicon, or an organic semiconductor material,a gate electrode 140, the source electrode 160 s, and the drainelectrode 160 d. A general structure of the thin film transistor TFTwill now be described.

A buffer layer 110 formed of silicon oxide, silicon nitride, or the likemay be disposed on the substrate 100 to planarize a surface of thesubstrate 100 or to prevent impurities or the like from penetrating intothe semiconductor layer 120 of the thin film transistor TFT, and thesemiconductor layer 120 may be on the buffer layer 110.

The gate electrode 140 may be disposed above the semiconductor layer120, and according to a signal applied to the gate electrode 140, thesource electrode 160 s and the drain electrode 160 d may be electricallyconnected to each other. The gate electrode 140 may include a singlelayer or layers including, for example, one or more materials selectedfrom aluminum (Al), platinum (Pt), palladium (Pd), silver (Ag),magnesium (Mg), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir),chromium (Cr), lithium (Li), calcium (Ca), molybdenum (Mo), titanium(Ti), tungsten (W), and copper (Cu) by taking into account factors suchas adhesiveness to an adjacent layer, surface smoothness of a stackedlayer, and processability.

In this regard, in order to secure insulation between the semiconductorlayer 120 and the gate electrode 140, a gate insulation layer 130including silicon oxide and/or silicon nitride may be between thesemiconductor layer 120 and the gate electrode 140.

An interlayer insulation layer 150 may be on the gate electrode 140 andmay include a single layer or layers formed of a material such assilicon oxide or silicon nitride.

The source electrode 160 s and the drain electrode 160 d may be on theinterlayer insulation layer 150. The source electrode 160 s and thedrain electrode 160 d may each be electrically connected to thesemiconductor layer 120 via contact holes in the interlayer insulationlayer 150 and the gate insulation layer 130. The source electrode 160 sand the drain electrode 160 d may include a single layer or layersincluding, for example, one or more materials selected from aluminum(Al), platinum (Pt), palladium (Pd), silver (Ag), magnesium (Mg), gold(Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium(Li), calcium (Ca), molybdenum (Mo), titanium (Ti), tungsten (W), andcopper (Cu) by taking into account a factor such as conductivity.

Although not illustrated, a protective layer (not shown) may be providedto cover the thin film transistor TFT for protection of the thin filmtransistor TFT having such a structure. The protective layer may beformed of an inorganic material, for example, silicon oxide, siliconnitride, or silicon oxynitride.

A planarization layer 170 may be disposed above the substrate 100. Whenan OLED is above the thin film transistor TFT, the planarization layer170 substantially planarizes the top surface of the thin film transistorTFT and protects the thin film transistor TFT and various devices. Theplanarization layer 170 may be formed of, for example, an acrylicorganic material or benzocyclobutene (BCB). In this regard, asillustrated in FIG. 3, the buffer layer 110, the gate insulation layer130, the interlayer insulation layer 150, and the first planarizationlayer 170 may be over the entire surface of the substrate 100.

The pixel-defining layer 180 may be disposed above the thin filmtransistor TFT. The pixel-defining layer 180 may be on the planarizationlayer 170 and may have an opening. The pixel-defining layer 180 definesa pixel area above the substrate 100. The pixel-defining layer 180 maybe, for example, an organic insulation layer. The organic insulationlayer may include an acrylic polymer such as poly(methyl methacrylate)(PMMA), polystyrene (PS), a polymer derivative containing a phenolgroup, an imide-based polymer, an aryl ether-based polymer, anamide-based polymer, a fluorine-based polymer, a p-xylene-based polymer,a vinyl alcohol-based polymer, and a mixture thereof.

The OLED may be on the pixel-defining layer 180. The OLED may include apixel electrode 210, the emission layer 223, and the opposite electrode230.

The pixel electrode 210 may be a (semi)transparent electrode or areflective electrode. When the pixel electrode 210 is a(semi)transparent electrode, the pixel electrode 210 may be formed of,for example, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide(ZnO), indium oxide (In₂O₃), indium gallium oxide (IGO), or aluminumzinc oxide (AZO). When the pixel electrode 210 is a reflectiveelectrode, the pixel electrode 210 may include a reflective layer formedof Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, and a compound thereof, and alayer including ITO, IZO, ZnO, In₂O₃, IGO, or AZO. However, thedisclosure is not limited thereto, and the pixel electrode 210 mayinclude various materials. Also, a structure of the pixel electrode 210may differ, such as a single layer or layers.

The emission layer 223 may be in the pixel area defined by thepixel-defining layer 180 and may be in the middle of the firstintermediate layer 221 and the second intermediate layer 222. The firstintermediate layer 221 may include an HIL and/or an HTL between theemission layer 223 and the pixel electrode 210, and the secondintermediate layer 222 may include an ETL and/or an EIL between theemission layer 223 and the opposite electrode 230. However, the firstand second intermediate layers 221 and 222 are not limited thereto andmay have various structures.

The opposite electrode 230 covering the first and second intermediatelayers 221 and 222 as well as the emission layer 223 and facing thepixel electrode 210 may be disposed over the entire surface of thesubstrate 100. The opposite electrode 230 may be a (semi)transparentelectrode or a reflective electrode.

When the opposite electrode 230 is a (semi)transparent electrode, theopposite electrode 230 may include a layer including metal having a lowwork function, that is, Li, Ca, LiF/Ca, LiF/Al, Al, Ag, Mg, and acompound thereof, and a (semi)transparent conductive layer includingITO, IZO, ZnO, In₂O₃, or the like. When the opposite electrode 230 is areflective electrode, the opposite electrode 230 may include a layerincluding Li, Ca, LiF/Ca, LiF/Al, Al, Ag, Mg, and a compound thereof.However, a structure and a material of the opposite electrode 230 arenot limited thereto and may vary.

Referring to FIG. 3, an auxiliary wiring 160 a may be on the same layeras the source electrode 160 s and the drain electrode 160 d. In thiscase, the auxiliary wiring 160 a does not necessarily have to be on thesame layer as the source electrode 160 s or the drain electrode 160 d.However, when the auxiliary wiring 160 a is on the same layer as thesource electrode 160 s or the drain electrode 160 d relatively thickerthan other conductive layers, it may be easy to decrease resistanceapplied to the auxiliary wiring 160 a.

The opposite electrode 230 may electrically contact the auxiliary wiring160 a via an opening 230 a. Referring to FIG. 3, a material layer 210 amay be further disposed between a portion of the opposite electrode 230that corresponds to the opening 230 a and the auxiliary wiring 160 a.The material layer 210 a may include the same material as the pixelelectrode 210 and may be on the same layer as the pixel electrode 210.

The opposite electrode 230 may electrically contact the auxiliary wiring160 a via the opening 230 a in the intermediate layer 221 and 222. Theopening 230 a may be formed by irradiating a laser beam on theintermediate layer 221 and 222, and accordingly, a portion of theintermediate layer 221 and 222 that is adjacent to the opening 230 a inthe intermediate layer 221 and 222 may be transformed by strong heat.For example, after the intermediate layer 221 and 222 is formed over theentire surface of the pixel-defining layer 180, a laser bean may beirradiated around the auxiliary wiring 160 a having at least a portionexposed by the pixel-defining layer 180, and thus, the opening 230 a maybe formed.

FIG. 4 is a schematic plan view of an OLED display 2 according to anembodiment. FIG. 5 is an enlarged view of part V of FIG. 4.

Referring to FIGS. 4 and 5, the OLED display 2 may further include aplurality of sub-wirings 140 a disposed perpendicular to the auxiliarywirings 160 a 1 to 160 an. The OLED display 2 in the present embodimentis identical to the OLED display 1 of FIGS. 1 to 3 except that thesub-wirings 140 a are additionally provided. Accordingly, thesub-wirings 140 a will be mainly described hereinafter, and repeateddescriptions thereof will be omitted.

The OLED display 2 may include the sub-wirings 140 a. As illustrated inFIG. 5, the sub-wirings 140 a may extend in the second direction (x-axisdirection) perpendicular to the first direction (y-axis direction). Thatis, the sub-wirings 140 a may cross the auxiliary wirings 160 a andthus, may form a mesh shape. The sub-wirings 140 a may be electricallyconnected to the auxiliary wirings 160 a via contact holes (not shown)in a position where the sub-wirings 140 a cross the auxiliary wirings160 a. Due to the sub-wirings 140 a, the amount of current passingthrough the auxiliary wirings 160 a may be easily dispersed. Althoughnot illustrated, the sub-wirings 140 a may be on the same layer as oneof the electrodes included in the thin film transistor TFT. For example,in the previous embodiment of FIG. 3, the sub-wirings 140 a may be onthe same layer as the gate electrode 140, and accordingly, thesub-wirings 140 a may be formed of the same material as the gateelectrode 140.

Although an OLED display according to one or more embodiments has beenmainly described above, the disclosure is not limited thereto. Forexample, a method of manufacturing an OLED display, according to one ormore embodiments, is within the scope of the described technology.

FIGS. 6 to 9 are schematic cross-sectional views of a process ofmanufacturing an OLED display according to an embodiment. Although aplurality of pixels have to be disposed in the display area DA of thesubstrate 100 in order to manufacture the OLED display according to anembodiment, the manufacturing process will be described with focus on across-sectional structure of one pixel with reference to FIGS. 6 to 9.

Referring to FIGS. 2 and 6, the pixel electrodes 210 that are separatefrom each other are disposed above the substrate 100. Although it isillustrated in FIG. 6 that the pixel electrode 210 is disposed on theplanarization layer 170, the disclosure is not limited thereto.

Various layers may be disposed before the pixel electrode 210 isdisposed. It is illustrated in FIG. 6 that, after the thin filmtransistor TFT and the capacitor CAP are disposed above the substrate100, and the planarization layer 170 covering the thin film transistorTFT and the capacitor CAP is disposed thereon, the pixel electrode 210is disposed on the planarization layer 170.

In this regard, before the pixel electrodes 210 are disposed, asillustrated in FIG. 2, the auxiliary wirings 160 a 1 to 160 an may bedisposed between the pixel electrodes 210 and be separate from eachother by a predetermined distance. The auxiliary wirings 160 a 1 to 160an may extend in the first direction (y-axis direction).

Referring to FIG. 6, the auxiliary wiring 160 a is disposed on the samelayer as the source electrode 160 s and the drain electrode 160 d of thethin film transistor TFT and is formed of the same material as thesource electrode 160 s and the drain electrode 160 d. However, thedisclosure is not limited thereto. Any conductive layer may be used toform the auxiliary wiring 160 a, and the auxiliary wiring 160 a may bedisposed on the same layer as the gate electrode 140 or the pixelelectrode 210.

Referring to FIG. 6 with FIG. 2, the formation of the auxiliary wirings160 a 1 to 160 an includes formation of the first auxiliary wiring 160 a1 and the second auxiliary wiring 160 a 2 separate from each other bythe second distance.

After the auxiliary wiring 160 a is disposed, the planarization layer170 may be disposed on the auxiliary wiring 160 a. In this regard, theplanarization layer 170 may expose at least a portion of the auxiliarywiring 160 a, and the exposed at least a portion of the auxiliary wiring160 a may electrically contact the opposite electrode 230. Theconductive material layer 210 a may be further disposed on the portionof the auxiliary wiring 160 a that is exposed by the planarization layer170. The material layer 210 a of FIG. 6 may be disposed on the samelayer as the pixel electrode 210.

Afterwards, referring to FIG. 6, the pixel-defining layer 180 isdisposed on the pixel electrode 210 so as to expose at least a portionof the pixel electrode 210 that includes a central portion of the pixelelectrode 210. In this regard, the pixel-defining layer 180 may exposeat least a portion of the material layer 210 a. Although, in the presentembodiment, the material layer 210 a is disposed on the auxiliary wiring160 a, and the pixel-defining layer 180 exposes at least a portion ofthe material layer 210 a, the disclosure is not limited thereto. Thematerial layer 210 a may not be disposed on the auxiliary wiring 160 a,and in this case, the pixel-defining layer 180 may directly expose atleast a portion of the auxiliary wiring 160 a.

Afterwards, the intermediate layer 221 and 222 and the emission layer223 may be over the entire surface of the substrate 100 to cover thepixel-defining layer 180. Although not illustrated, the intermediatelayer 221 and 222 may be integrally formed with each other on aplurality of pixels. For example, the first intermediate layer 221 isformed to cover the pixel-defining layer 180 and the pixel electrode210, and then, the emission layer 223 may be formed so as to correspondto the pixel electrode 210. Afterwards, the second intermediate layer222 may be formed to cover the emission layer 223 and the firstintermediate layer 221.

For example, the first intermediate layer 221 includes an HIL and/or anHTL, and the second intermediate layer 222 may include an ETL and/or anEIL.

Afterwards, as illustrated in FIG. 8, a portion of the firstintermediate layer 221 that is above the auxiliary wiring 160 a and aportion of the second intermediate layer 222 that is above the auxiliarywiring 160 a are removed to form the opening 221′ in the firstintermediate layer 221 and the opening 222′ in the second intermediatelayer 222, and thus, at least a portion of the auxiliary wiring 160 a isexposed. For this, as illustrated in FIG. 7, a laser beam may beirradiated on the second intermediate layer 222, and thus, the opening221′ and the opening 222′ may be respectively formed in the firstintermediate layer 221 and the second intermediate layer 222simultaneously (or concurrently).

The openings 230 a formed by using such a method may be, as illustratedin FIG. 2, in the diagonal direction (direction A) crossing the firstdirection (y-axis direction) in which the auxiliary wirings 160 a 1 to160 an extend. The openings 230 a may be shifted as much as apredetermined distance in the diagonal direction (direction A).

The formation of the openings 230 a may include formation of the firstopening 230 a 1 exposing at least a portion of the first auxiliarywiring 160 a 1 and the second opening 230 a 2 exposing at least aportion of the second auxiliary wiring 160 a 2. In this case, the secondopening 230 a 2 may be shifted from the first opening 230 a 1 by apredetermined distance. In this regard, since the first auxiliary wiring160 a 1 and the second auxiliary wiring 160 a 2 are separate from eachother by the second distance, the second opening 230 a 2 may be shiftedfrom the first opening 230 a 1 by the second distance. In this regard,the second distance may be the same as the first distance d or may be ntimes the first distance d. That is, when the second distance is thesame as the first distance d, the second auxiliary wiring 160 a 2 may beright next to the first auxiliary wiring 160 a 1. When the seconddistance is n times the first distance d, the second auxiliary wiring160 a 2 may not be right next to the first auxiliary wiring 160 a 1.

Referring to FIG. 2, the formation of the openings 230 a may furtherinclude formation of the third opening 230 a 3 and the fourth opening230 a 4 in addition to the first opening 230 a 1 and the second opening230 a 2. The third opening 230 a 3 may be most adjacent to the firstopening 230 a 1 in the second direction (x-axis direction) perpendicularto the first direction (y-axis direction). Similarly, the fourth opening230 a 4 may be most adjacent to the second opening 230 a 2 in the seconddirection (x-axis direction) perpendicular to the first direction(y-axis direction). In this regard, a shape obtained by connectingrespective vertices of the first opening 230 a 1, the second opening 230a 2, the third opening 230 a 3, and the fourth opening 230 a 4 may be aparallelogram. That is, when the first opening 230 a 1 and the thirdopening 230 a 3 are parallel to each other in the second direction(x-axis direction), and the second opening 230 a 2 and the fourthopening 230 a 4 are also parallel to each other in the second direction(x-axis direction), the second opening 230 a 2 is shifted from the firstopening 230 a 1 by a predetermined distance in the diagonal direction(direction A), and the fourth opening 230 a 4 is shifted from the thirdopening 230 a 3 by a predetermined distance in the diagonal direction(direction A).

When the first opening 230 a 1 and the second opening 230 a 2 are not inthe diagonal direction (direction A) but consecutively in the firstdirection (y-axis direction) along a certain auxiliary wiring, forexample, the first auxiliary wiring 160 a 1, current concentrates intothe first auxiliary wiring 160 a 1. This degrades the performance of anauxiliary wiring formed to lower the IR drop of the opposite electrode230. Accordingly, in the OLED display 1 according to an embodiment, whenthe openings 230 a via which the auxiliary wirings 160 a 1 to 160 an andthe opposite electrode 230 may electrically contact each other areformed, the openings 230 a may be shifted as much as a predetermineddistance in the diagonal direction (direction A) and thus may be abovedifferent auxiliary wirings from each other. Accordingly, current may beprevented from concentrating into a certain auxiliary wiring.

Next, as illustrated in FIG. 9, the opposite electrode 230 correspondingto the pixel electrode 210 and the auxiliary wiring 160 a is formed soas to electrically contact the auxiliary wiring 160 a via the opening230 a. The opposite electrode 230 may be formed as one body with respectto the plurality of pixels to cover a display area (active area). Inthis regard, the display area may refer to any area of the entire OLEDdisplay, from which light may be emitted. For example, the display areamay refer to all areas except an edge of the OLED display, where acontroller or the like is disposed. When there is no dead area over theentire surface of the OLED display, the entire surface of the OLEDdisplay may be referred to as the display area. The opposite electrode230 may contact an electrode power supply line outside of the displayarea and receive an electrical signal from the electrode power supplyline.

According to at least one of the disclosed embodiments, an OLED displaythat is easy to manufacture and has high emission stability and a methodof manufacturing the OLED display may be provided. However, such aneffect does not pose a limitation on the scope of the describedtechnology.

It should be understood that embodiments described herein should beconsidered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each embodimentshould typically be considered as available for other similar featuresor aspects in other embodiments.

While the inventive technology has been described with reference to thefigures, it will be understood by those of ordinary skill in the artthat various changes in form and details may be made therein withoutdeparting from the spirit and scope as defined by the following claims.

What is claimed is:
 1. A method of manufacturing an organiclight-emitting diode (OLED) display, the method comprising: forming aplurality of pixel electrodes over a substrate, the pixel electrodesbeing separate from each other; forming a plurality of auxiliary wiringsbetween the pixel electrodes, the auxiliary wirings extending in a firstdirection and separate from each other by a first distance; forming apixel-defining layer over the pixel electrodes except for a centralportion of the pixel electrodes and at least a portion of each of theauxiliary wirings; forming an intermediate layer over the entire surfaceof the substrate, the intermediate layer covering the pixel-defininglayer; forming a plurality of openings in the intermediate layer thatrespectively expose at least a portion of each of the auxiliary wirings,wherein the openings are aligned in a diagonal direction crossing thefirst direction; and forming an opposite electrode that faces the pixelelectrodes over the intermediate layer, the opposite electrodeelectrically contacting the auxiliary wirings via the openings.
 2. Themethod of claim 1, wherein the forming of the openings comprisesirradiating a laser beam on the intermediate layer.
 3. The method ofclaim 1, wherein the forming of the auxiliary wirings comprises forminga first auxiliary wiring and forming a second auxiliary wiring separatefrom the first auxiliary wiring by a second distance, and wherein theforming of the openings comprises forming a first opening that exposesat least a portion of the first auxiliary wiring and forming a secondopening that exposes at least a portion of the second auxiliary wiring.4. The method of claim 3, wherein the second distance is to the same asthe first distance.
 5. The method of claim 3, wherein the seconddistance is n times longer the first distance, and wherein n is anatural number.
 6. The method of claim 3, wherein the forming of theopenings comprises i) forming a third opening that is located closest tothe first opening in a second direction crossing the first direction andii) forming a fourth opening that is located closest to the secondopening in the second direction and wherein the first to fourth openingshave a parallelogram shape.
 7. The method of claim 1, further comprisingforming an emission layer between the pixel electrodes and the oppositeelectrode.